Design of ionic liquid-based microwave-assisted extraction of flavonoids from Cyclea barbata Miers. And its lipoxygenase inhibitory activity

Green grass jelly (Cyclea barbata Miers.) is a plant from Indonesia that is believed to have anti-inflammatory activity. This study aims to find the optimum condition in grass jelly extraction using the ionic liquid-microwave assisted extraction toward total flavonoid content (TFC) and lipoxygenase activity (LIA). The experimental design was performed using the parameters variable including extraction time, liquid-solid ratio, and ionic liquids concentration to obtain the optimum condition. The optimization analysis used response surface methodology (RSM) with Box-Behnken design (17 trials) to obtain a predictive model with TFC and LIA as a response surface value. In the present study, the optimum condition was suggested by RSM analysis with parameter variables, including extraction time of 17 minutes, 1-butyl-3-methylimidazolium bromide ([BMIM]Br) concentration of 1.76 mol/l, and the liquid-solid ratio of 38.21 ml/g. The equation of regression quadratic model was obtained to predict TFC and LIA as follows: TFC = 2.43A + 2.43B + 1.42C + 0.33AB-3.20AC-0.46BC-4.90A2-3.10B²-3.10C² + 28.32 with R² = 0.8336 and LIA = 0.066A + 8.22B + 0.97C + 2.47AB-5.86AC + 1.96BC-9.99A²-13.75B²-13.11C² + 63.53 with R² = 0.9207, respectively.